Buffy is engaged to Angel/Liam but starts having an affair with his brother Spike

Buffy is engaged to Liam/Angel (I can't remember which name was used) and she starts having an affair with his bad boy brother Spike.

Possibly:

Perfectly Opposite by Shannon Ridley

http://www.fanfiction.net/s/2713135/1/Perfectly_Opposite

Summary: Buffy Summers is engaged to the perfect man and there's nothing to stop her from marrying him and having the perfect life. That is, until she meets his brother.

Is it Comedown by Elanor?

Summary: AU Buffy Summers has been asked to move in with her boyfriend Angel Giles, heir to the law firm of Wolfram and Hart. But when Angel's rebel younger brother, Spike, returns to claim what is rightfully his, Buffy sees Angel in a new light as sparks fly between Spike and herself. Angel continues to plow ahead in the relationship, and Spike brings her to question her choices in life. Will she follow her current path or follow her heart?

Its a great story!

Anyone know this???

I guess it's one of those two and since the original poster hasn't confirmed nor denied it I'm moving this to FOUND!!